Anchoring An Intravenous Cannula

ABSTRACT

Some embodiments of a medical system include a subcutaneous anchor device that extends outwardly from side wall of an intravenous cannula so as to secure the intravenous cannula in a position relative to a skin penetration point.

TECHNICAL FIELD

This document relates to a medical device having an integrated anchorsystem for securing a portion of the medical device in a subcutaneousregion underlying the skin.

BACKGROUND

Some medical devices a configured to provide intravenous therapy inwhich and an intravenous infusion of a fluid is administered through anintravenous cannula. The intravenous cannula normally includes a distaltip region that is configured to insert through a skin opening and intoa selected body vessel (e.g., a vein in a patient's arm or leg) while aproximal hub remains external to skin opening for connection with aseparate medicinal fluid line. This type of intravenous infusion therapyprovides a direct route to the bloodstream which allows for hydration,administration of blood or blood products and administration ofmedications. Medications that are administered intravenously can achievetherapeutic effects more rapidly and, in some cases, using a lower dose.

Typical intravenous cannulas may extend for several inches in length andnormally include a fluid lumen that extends to a distal port and the tipof the cannula. In some version, the intravenous cannula may includelarge, flat “wings” or “tabs” that remain external to the skin and areequipped to adhere to the outer surface of the patient's skin. In othercircumstances, the intravenous cannula may be secured to the skinpenetration site using adhesive tape that is wrapped around an outercircumferential surface region of the intravenous cannula and around anadjacent portion of the patient's arm or leg.

SUMMARY

Some embodiments of a medical system include a subcutaneous anchordevice that extends outwardly from side wall of an intravenous cannulaso as to secure the intravenous cannula in a position relative to a skinpenetration point. In some circumstances, the subcutaneous anchor devicecan be integrally formed as a unitary structure with the side wall ofthe intravenous cannula so that the subcutaneous anchor device ispositioned along a central region of the intravenous cannula (e.g., at aposition that is proximal of the distal tip portion configured topenetrate into a targeted vein or other vessel, and that is distal ofthe proximal connector hub configured to releasably mate with a separatefluid line). As such, the subcutaneous anchors may engage with fattytissue or other tissue inside the subcutaneous layer immediatelyunderlying the skin near the skin penetration point, thereby providingan anchoring effect without necessarily requiring adhesives appliedexternal to the skin.

Some embodiments described herein include a medical system for anchoringan intravenous cannula device in a subcutaneous region along anunderside of a skin layer. The medical system may include an intravenouscannula device and an inserter tool removably coupled to the intravenouscannula device. The intravenous cannula device may include a flexiblecatheter, a proximal connector hub, and a subcutaneous anchor integrallyformed as a unitary structure with an outer wall of the flexiblecatheter. The flexible catheter may include a lumen and also may extenddistally of the proximal connector hub. The proximal connector hub mayoptionally include a thread pattern configured to releasably connectwith an external fluid line. The inserter tool may be removably coupledto the intravenous cannula device so as to insert the flexible catheterof the intravenous cannula device through a skin penetration point andinto a targeted vessel. The inserter tool may optionally include ahandle and an insertion needle extending distally from the handle. Theinsertion needle may be slidably engaged with the lumen of the flexiblecatheter of the intravenous cannula device. The inserter tool may beremovable from the intravenous cannula device when the insertion needleis proximally withdrawn from the lumen of the flexible catheter. Thesubcutaneous anchor of the intravenous cannula device may be positionedbetween a distal tip of the flexible catheter and the proximal connectorhub. The subcutaneous anchor may include at least one surface to engagetissue in a subcutaneous region along an underside of a skin layer whenthe flexible catheter of the intravenous cannula device is insertedthrough a skin penetration point and into a targeted vessel.

Particular embodiments include a method of using an intravenous cannuladevice. The method may include inserting a needle portion of an insertertool through a skin penetration point and into a targeted vessel. Anintravenous cannula device may be removably coupled to the inserter toolsuch that a flexible catheter of the intravenous cannula device isadvanced through the skin penetration point and into the targeted vesselwhile a subcutaneous anchor integrally formed as a unitary structurewith an outer wall of the flexible catheter is positioned in asubcutaneous region along an underside of a skin layer. The method mayalso include removing the inserter tool from the intravenous cannuladevice such that the needle portion of the inserter tool is slidablywithdrawn from a lumen of the flexible catheter while the flexiblecatheter remains in the targeted vessel and the subcutaneous anchorremains in the subcutaneous region along the underside of the skinlayer. Optionally, the method may include threadably engaging anexternal fluid line to a proximal connector hub of the intravenouscannula device while the flexible catheter remains in the targetedvessel and the subcutaneous anchor remains in the subcutaneous regionalong the underside of the skin layer. The subcutaneous anchor may bepositioned between a distal tip of the flexible catheter and theproximal connector hub. The subcutaneous anchor may include at least onesurface to engage tissue in the subcutaneous region proximate to theskin penetration point.

In other embodiments, a medical system for anchoring an intravenouscannula device in a subcutaneous region along an underside of a skinlayer may include an intravenous cannula device. The intravenous cannuladevice may include a flexible catheter, a proximal connector hub, and asubcutaneous anchor positioned between a distal tip of the flexiblecatheter and the proximal connector hub, The system may also include aninserter tool removably coupled to the intravenous cannula device. Theinserter tool may optionally include a handle and an insertion needleextending distally from the handle. The insertion needle may be slidablyengaged with a lumen of the flexible catheter. The subcutaneous anchormay include at least one surface to engage tissue in a subcutaneousregion along an underside of a skin layer when the flexible catheter ofthe intravenous cannula device is into a targeted vessel.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIGS. 1-3 are perspective views of an intravenous cannula system havinga subcutaneous anchor, in accordance with some embodiments.

FIGS. 4A and 4B are perspective and side views of an intravenous cannulasystem having a subcutaneous anchor including a circumferential ring, inaccordance with some alternative embodiments.

FIGS. 5A and 5B are perspective and side views of an intravenous cannulasystem having subcutaneous anchors including a multiple circumferentialring, in accordance with some alternative embodiments.

FIGS. 6A and 6B are perspective and side views of an intravenous cannulasystem having subcutaneous anchors including a pair of recessed tabs, inaccordance with some alternative embodiments.

FIGS. 7A and 7B are perspective and side views of an intravenous cannulasystem having subcutaneous anchors including multiple pairs of recessedtabs, in accordance with some alternative embodiments.

FIGS. 8A and 8B are perspective and side views of an intravenous cannulasystem having a subcutaneous anchor including a slotted circumferentialring, in accordance with some alternative embodiments.

FIGS. 9A and 9B are perspective and side views of an intravenous cannulasystem having subcutaneous anchors including multiple slottedcircumferential rings, in accordance with some alternative embodiments.

FIGS. 10A and 10B are perspective and side views of an intravenouscannula system having a subcutaneous anchor including an anchor flap, inaccordance with some alternative embodiments.

FIGS. 11A and 11B are perspective and side views of an intravenouscannula system having subcutaneous anchors including multiple anchorflaps, in accordance with some alternative embodiments.

FIGS. 12A and 12B are perspective and side views of an intravenouscannula system having a subcutaneous anchor including a taperedcircumferential ring, in accordance with some alternative embodiments.

FIGS. 13A and 13B are perspective and side views of an intravenouscannula system having subcutaneous anchors including multiple taperedcircumferential rings, in accordance with some alternative embodiments.

FIGS. 14A and 14B are perspective and side views of an intravenouscannula system having subcutaneous anchors including textured cutouts,in accordance with some alternative embodiments.

FIGS. 15A and 15B are perspective and side views of an intravenouscannula system having a subcutaneous threaded anchor, in accordance withsome alternative embodiments.

FIGS. 16A and 16B are perspective and side views of an intravenouscannula system having a subcutaneous anchor including a wedge, inaccordance with some alternative embodiments.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIGS. 1-3, a medical system 100 includes an intravenouscannula device 105 that is equipped with a subcutaneous anchor 130 so asto secure the intravenous cannula device 105 in a position relative to askin penetration point 32. In this embodiment, the subcutaneous anchor130 can be integrally formed as a unitary structure with the side wallof the intravenous cannula device 105. The intravenous cannula device105 can include a distal section having a flexible catheter 120 and aproximal connector hub 115 configured to releasably connect with anexternal fluid line (not shown in FIGS. 1-3). As described in moredetail below, the subcutaneous anchor 130 can be positioned along acentral region of the intravenous cannula 105 such that the anchor 130is arranged proximal to a distal tip 122 of the catheter 120 and isarranged distal to the proximal connector hub 115. In particularembodiments, the subcutaneous anchor 130 is located in the centralregion 107 and extends radially outward of a cylindrical wall thecatheter 120 so that the subcutaneous anchor 130 may engage with fattytissue or other tissue inside the subcutaneous layer 34 immediatelyunderlying the skin 30 near the skin penetration point 32, therebyproviding an anchoring effect without necessarily requiring adhesivesapplied external to the skin 30.

The system 100 depicted in FIGS. 1-3 also includes an inserter tool 110(FIG. 3) that is detachably connected to the intravenous cannula device105. In this embodiment, the inserter tool 110 includes a handle 112configured to be grasped by a user in order to control the insertion ofthe intravenous cannula device 105 through the skin penetration point32. As described in more detail below, the inserted tool 110 isremovably coupled to the intravenous cannula device 105 so that aninsertion needle 125 of the inserter tool 110 provides support to theflexible catheter 120 during insertion of the distal tip 122 of theflexible catheter 120 into a targeted body vessel 40. After the insertertool 110 is used to facilitate placement of the intravenous cannuladevice 105, the inserter tool 110 can be removed from the intravenouscannula device 105 while the distal tip 122 of the flexible catheter 120remains in the targeted body vessel 40, thereby providing a fluidcommunication line between the proximal connector hub 115 and thetargeted body vessel 40 via the flexible catheter 120.

Still referring to FIGS. 1-3, the proximal connector hub 115 of theintravenous cannula device 105 includes a fluid fitting 117 that isconfigured to releasably mate with an external fluid line. For example,the fluid fitting 117 may provide a luer connector, which includes athreaded region and a sealing face at the proximal-most end region ofthe proximal connector hub 115, for purposes of detachably coupling toan external fluid line (e.g., a supply of intravenous fluid, a medicinedelivery line, a blood infusion line, a blood withdrawal line, or thelike). The proximal connector hub 115 includes a generally rigid bodyhaving an outer radius that is substantially larger than the outerradius of the flexible catheter 120. In this embodiment, the outerradius of the proximal connector hub 115 is also larger than the skinpenetration point 32 such that the proximal connector hub 115 remainsexternal to the skin 30 during use. The proximal connector hub 115includes a central lumen that is in fluid communication with acorresponding lumen of the flexible catheter 120. Accordingly, in theembodiment depicted in FIGS. 1-3, the catheter 120 can be inserted intothrough the penetration point 32, to the underside of the skin 30, andinto a vein 40 or other targeted vessel to provide vascular access forintravenous infusion or withdrawal of a fluid.

In some embodiments, the catheter 120 may be flexible. For example, thecatheter 120 can be configured to flexibly contour with the curvaturesof the targeted vessel 40. As previously described, the catheter 120 canbe supported by the insertion needle 125 on the inserter tool 110 duringthe initial placement of the flexible catheter 120 into the targetedvessel 40. In such embodiments, the insertion needle 125 removablyoccupies the lumen of the catheter 120, and provides support for thecatheter 120 against bending or bucking during insertion into thetargeted vessel 40. In some implementations, the insertion needle 125 isequipped with a sharp tip 127 that protrudes from the distal tip of thecatheter 120 (refer to FIGS. 1-2) such that the inserter tool 110provides the initial penetration path through the skin 32 and into thetargeted vessel 40.

The catheter 120 can be configured to have an axial length which issubstantially greater than the axial length of the proximal connectorhub 115. For example, in some embodiments, the axial length of thecatheter 20 (extending from the junction with the proximal connector hub115 to the distal-most end of the catheter tip) can be about 25 mm toabout 150 mm, about 40 mm to about 70 mm, and preferably about 50 mm.The catheter may also include an outer diameter of about 12-gauge toabout 28-gauge, and preferable about 14-gauge to about 24-gauge sizes.Such an axial length and diameter size can be advantageous for providingaccess to the targeted vessel 40 while not necessary requiringadvancement deep into the vasculature. Also, the overall axial length ofthe intravenous cannula device 105 (extending from the proximal end ofthe proximal connector hub 115 to the distal-most end of the cathetertip) can be about 45 mm to about 170 mm, about 60 mm to about 90 mm, andpreferably about 70 mm. Such an axial length can be advantageous forproviding access to the targeted vessel while also maintaining theproximal connector hub 115 at a location external to the skin and nearthe skin penetration point 32.

Still referring to FIGS. 1-3, the flexible catheter 120 can extenddistally from the proximal connector hub 115, and the proximal portionof the flexible catheter can define the central region 107 of theintravenous cannula device 105 at which the subcutaneous anchor 130 islocated. In this embodiment, the subcutaneous anchor 130 is formed aboutthe periphery of the catheter 120 at a position that is substantiallycloser to the proximal connector hub 115 than to the distal tip 122 ofthe catheter 120. The subcutaneous anchor 130 is positioned to reside inthe subcutaneous layer 34 along the underside of the skin 30 and nearthe skin penetration point 32. Accordingly, while the catheter 120 canpenetrate into the targeted vessel 40, the subcutaneous anchor 130 ispositioned along to the intravenous cannula device 105 to resideexternal to the vessel 40 but under the skin 30 in the subcutaneouslayer 34. Furthermore, while the subcutaneous anchor 130 is positionedin the subcutaneous layer 34, the proximal connector hub 115 remainsexternal to the skin 30 so as to receive a connection with an externalfluid line.

As described in more detail below, the subcutaneous anchor 130 can bedirected to penetrate through the same penetration point 32 as thecatheter 120 to maintain a position of the subcutaneous anchor 130 inthe subcutaneous layer 34 along the underside of the skin 30. As such,the subcutaneous anchor 130 can secure the catheter 120 in the operativeposition relative to the penetration point 32 without necessarilyrequiring adhesives bonded to the skin. In some embodiments, thesubcutaneous anchor 130 can be integrally formed with the catheter 120as a unitary such that the subcutaneous anchor 130 and the catheter 120share a common material. The subcutaneous anchor 130 can include one ormore structures that extend outwardly from outer circumference of thecatheter 120. For example, the subcutaneous anchor 130 can include oneor more rings, flexible flaps, spirals, flexible tabs, tines, barbs, orthe like that, after insertion, are deployed in the subcutaneous region34 so as to secure the position of the intravenous cannula device 105relative to the skin penetration point 32. Various examples of thesubcutaneous anchor 130 are described below in connection with FIGS.4-16.

In use, the system 100 can be manipulated by a user so as to deliver thedistal tip of intravenous cannula device 105 into the targeted vessel40, and then the system 100 can be adjusted to provide a fluidcommunication line to the targeted vessel 40. For example, as shown inFIG. 1, the handle 112 of the inserter tool 110 can be grasped by theuser so as to forcibly advance the sharp tip 127 of the insertion needle125 through the skin 30 and into the targeted vessel 40. In doing so,the flexible catheter 120 of the intravenous cannula device 105 (whichis slidably received on the insertion needle 125) is also advancedthrough the penetration point 32 and into the targeted vessel 40.

As shown in FIG. 2, the system 100 can be further advanced after theskin penetration point 32 is formed so that the subcutaneous anchor 130is likewise advanced through the skin penetration point 32. In suchcircumstances, the subcutaneous anchor 130 is positioned external to thevessel 40 but under the skin 30 in the subcutaneous layer 34. Thesubcutaneous anchor 130 includes one or more structures that areconfigured to engage the underside of the skin 30, the fatty tissues inthe subcutaneous layer 34, or both so as to resist withdrawal of theintravenous cannula device 105 from the skin penetration point 32. Thus,the intravenous cannula device 105 is anchored in the operative positionrelative to the penetration point 32 so that the distal tip of theflexible catheter 120 resides in the targeted vessel 40 while theproximal connector hub 115 resides external to the skin 30. Preferably,the proximal connector hub 115 comprises a substantially transparentpolymer material so that the user can directly visualize blood returnfilling into an internal chamber at the hub when the distal end of thecatheter 120 is positioned within the vessel 40.

After the intravenous cannula device 105 is anchored in the operativeposition, the inserter tool 110 of the system can be released from theintravenous cannula device 105. For example, the inserter tool 110 canbe frictionally or threadably engaged with the intravenous cannuladevice 105. If the inserter tool 110 is engaged with the intravenouscannula device 105 by a friction fit, the user can apply a withdrawalforce to the handle 112 of the inserter tool 110 relative to theintravenous cannula device 105. If the inserter tool is threadablyengaged with the intravenous cannula device 105, the user can applied arotational motion to the handle 112 of the inserter tool 110 relative tothe intravenous cannula device 105 so as to decouple to the twocomponents. In the illustrated example in FIG. 2, the inserter tool 110can be released from the intravenous cannula device 105 by twisting(e.g., unscrewing) the handle 112 relative to the intravenous cannuladevice 105.

As shown in FIG. 3, after the intravenous cannula device 105 is anchoredin the operative position, the inserter tool 110 can be fully removedfrom the intravenous cannula device 105. In the illustrated example, theneedle 125, which had occupied the interior space of the catheter 120 inFIGS. 1 and 2, has been longitudinally withdrawn from the catheter 120through the proximal connector hub 115. As such, the needle 125 nolonger reinforces the flexible catheter 120, and allows the catheter 120to flexibly comply with curvatures of the vein 40 (e.g., in the event ofpatient movement). Furthermore, the central lumen of the catheter 120 isthen free to provide fluid communication between the proximal connectorportion 115 and the targeted vessel 40. Accordingly, the proximalconnector hub 115 can be mated with an external fluid line, such as anIV drip line or a medicine infusion line.

In some alternative embodiments, the inserter tool 110 can be equippedwith a retractable needle (rather than the fixed needle 125 that canreceive a safety cap after removal). The retractable needle of theinserter tool may be retractable relative to the handle 112, which canimprove user safety and reduce the likelihood of inadvertent needlewounds. For example, the retractable needle may have a length that issimilar to the needle 124 depicted in FIG. 3, but the retractable needlecan be spring-loaded to ejected proximally away from the lumen of theflexible catheter and into an internal receiving chamber defined insidethe handle 112 when the inserter tool is withdrawn from the intravenouscannula device 105. In such circumstances, the handle may have a greaterlength than the embodiment depicted in FIG. 3 so as to fully receive theretracted needle). Alternatively or additionally, the inserter tool canbe equipped with a protective cap piece that is movable to cover the tipof the needle (either the fixed needle 125 or the spring-biasedretractable needle) when the inserter tool is withdrawn from theintravenous cannula device 105.

In the embodiment depicted in FIGS. 1-3, the subcutaneous anchor 130 isintegrally formed with the outer wall of the flexible catheter 120. Theshape of the anchor device 130 can be selected to provide improvedanchoring or withdrawal benefits depending upon the configuration of thecatheter 120 and the selected location of the skin penetration pointalong a patient's body. For example, as shown in FIGS. 1-3, thesubcutaneous anchor 130 can include a tapered ring structure thatextends around the circumference of the catheter 120 and provides asubstantially greater outer diameter size than the generally cylindricalbody portion of the catheter 120. The tapered ring structure can have atapered wall that extends toward the distal tip 122 of the catheter 120so as to facilitate insertion through the skin penetration point 32,while a proximal-facing ridge of the subcutaneous anchor device 130resists withdrawal of the intravenous cannula device 105 while thesubcutaneous anchor device 130 resides in the subcutaneous layer 34. Insome alternative embodiments, the subcutaneous anchor device 130 can beprovided in different forms along the central region 107 of theintravenous cannula device 105.

Referring now to FIGS. 4A-4B, some alternative embodiments of a medicalsystem 400 may include a subcutaneous anchor 430 having a differentconfiguration, for example, in the shape of a flexible circumferentialring. In this embodiment, the medical system 400 can be similar to themedical system 100 of FIGS. 1-3. For example, the medical system 400includes an intravenous cannula device 405 and an inserter tool 410 thatis detachably coupled to the intravenous cannula device 405. Theintravenous cannula device 405 can include a distal section having aflexible catheter 420 and a proximal connector hub 415 configured toreleasably connect with an external fluid line (not shown in FIGS.4A-4B). In this embodiment, the flexible circumferential ring 430 isintegrally formed as a unitary structure with the side wall of theflexible catheter 420, and the flexible circumferential ring 430 ispositioned along a central region of the intravenous cannula device 405(e.g., proximal to a distal tip of the catheter 420 and distal to theproximal connector hub 415).

The flexible circumferential ring 430 is formed radially about thecatheter 420 at a location near to the proximal connector hub 415. Theflexible circumferential ring 430 can be directed to penetrate throughthe same penetration point 32 as the catheter 420 for positioning in inthe subcutaneous layer 34 along the underside of the skin 30. As such,the flexible circumferential ring 430 can secure the catheter 420 in theoperative position relative to the penetration point 32 withoutnecessarily requiring adhesive tapes bonded to the skin. In someembodiments, the flexible circumferential ring 430 can be integrallyformed with the flexible catheter 420 such that the flexiblecircumferential ring 430 and the catheter 420 share a common flexiblepolymer material. Accordingly, during insertion through the skinpenetration point, the flexible circumferential ring 430 can flexiblyadjust in a first direction so that the outer rim of the flexiblecircumferential ring 430 is shifted toward the circumferential wall ofthe catheter 420 (in a proximal direction toward the proximal connectorhub 415). After insertion of the flexible circumferential ring 430through the skin penetration point and into the subcutaneous layer 34,the flexible circumferential ring 430 can be biased to extend outwardlyfrom the circumferential wall of the catheter 420. In doing so, theflexible circumferential ring 430 can operate as a subcutaneous anchorthat engages the underside of the skin 30, the fatty tissues in thesubcutaneous layer 34, or both so as to resist withdrawal of theintravenous cannula device 405 from the skin penetration point 32. Thus,the intravenous cannula device 405 can be anchored in the operativeposition relative to the penetration point 32 so that the distal tip ofthe flexible catheter 420 resides in the targeted vessel 40 while theproximal connector hub 415 resides external to the skin 30.

Referring to FIG. 4B, during removal of the intravenous cannula device405, the flexible circumferential ring 430 can flexibly adjust in asecond direction so that the outer rim of the flexible circumferentialring 430 is shifted toward the circumferential wall of the catheter 420(in a distal direction away the proximal connector hub 415). Thus, theflexible circumferential ring 430 can be configured to prolapse inresponse to a removal force 440 applied to the intravenous cannuladevice 405 during withdrawal of the intravenous cannula device 405 fromthe skin penetration point.

Referring now to FIGS. 5A-5B, some alternative embodiments of a medicalsystem 500 may include an intravenous cannula device 505 that is similarto the device 405 illustrated in FIGS. 4A-4B, except that intravenouscannula device 505 is equipped with multiple subcutaneous anchors 530 inthe shape of flexible circumferential rings. Similar to previouslydescribed embodiments herein, the medical system 500 includes theintravenous cannula device 505 and an inserter tool 510 that isdetachably coupled to the intravenous cannula device 505. Theintravenous cannula device 505 can include a distal section having aflexible catheter 520 and a proximal connector hub 515 configured toreleasably connect with an external fluid line. In this embodiment, eachof the flexible circumferential rings 530 is integrally formed as aunitary structure with the side wall of the flexible catheter 520, andthe flexible circumferential rings 530 are positioned in series along acentral region of the intravenous cannula device 505 (e.g., proximal toa distal tip of the catheter 520 and distal to the proximal connectorhub 515).

Similar to the embodiments previously described in connection with FIGS.4A-4B, one or more of the flexible circumferential rings 530 can bedirected to penetrate through the same penetration point 32 as thecatheter 520 for positioning in in the subcutaneous layer 34 along theunderside of the skin 30. As such, one or more of the flexiblecircumferential rings 530 can secure the catheter 520 in the operativeposition relative to the penetration point 32 without necessarilyrequiring adhesive tapes bonded to the skin. Each of the flexiblecircumferential rings 530 inserted through the skin penetration point 32can flexibly adjust in a first direction so that the outer rim of therespective circumferential ring 530 is shifted toward thecircumferential wall of the catheter 520 (in a proximal direction towardthe proximal connector hub 515). After insertion of the respectivecircumferential ring 530 through the skin penetration point 32 and intothe subcutaneous layer 34, the respective circumferential ring 530 canbe biased to extend outwardly from the circumferential wall of thecatheter 520. In doing so, the respective circumferential ring 530 canoperate as a subcutaneous anchor that engages the underside of the skin30, the fatty tissues in the subcutaneous layer 34, or both so as toresist withdrawal of the intravenous cannula device 505 from the skinpenetration point 32. Thus, the intravenous cannula device 505 can beanchored in the operative position relative to the penetration point 32so that the distal tip of the flexible catheter 520 resides in thetargeted vessel 40 while the proximal connector hub 515 resides externalto the skin 30.

Referring to FIG. 5B, during removal of the intravenous cannula device505, each of the flexible circumferential rings 530 passing through theskin penetration point 32 can flexibly adjust in a second direction sothat the outer rim of the respective circumferential ring 530 is shiftedtoward the circumferential wall of the catheter 520 (in a distaldirection away the proximal connector hub 515). Thus, the respectivecircumferential ring 530 withdrawing through the skin penetration point32 can be configured to prolapse in response to a removal force 540applied to the intravenous cannula device 505 during withdrawal of theintravenous cannula device 505 from the skin penetration point. Any ofthe flexible circumferential rings 530 that are withdrawn through theskin penetration point 32 or are otherwise positioned external to theskin 30 can return to its non-prolapsed condition in which the flexiblecircumferential ring 530 is biased to extend generally radially outwardfrom the circumferential wall of the catheter 520.

Referring now to FIGS. 6A-6B, some alternative embodiments of a medicalsystem 600 may include a subcutaneous anchor 630 having a differentconfiguration, for example, in the shape of a pair of recessed tabs. Inthis embodiment, the medical system 600 can be similar to the medicalsystem 100 of FIGS. 1-3. For example, the medical system 600 includes anintravenous cannula device 605 and an inserter tool 610 that isdetachably coupled to the intravenous cannula device 605. Theintravenous cannula device 605 can include a distal section having aflexible catheter 620 and a proximal connector hub 615 configured toreleasably connect with an external fluid line. In this embodiment, eachof the recessed tabs 630 are integrally formed as a unitary structurewith the side wall of the flexible catheter 620, and the recessed tabs630 are positioned along a central region of the intravenous cannuladevice 605 (e.g., proximal to a distal tip of the catheter 620 anddistal to the proximal connector hub 615).

Each recessed tab 630 can include a corresponding cavity 632 that isshaped to receive the respective recessed tab 630 during insertionthrough the skin penetration point 32. Also, the pair of recessed tabs630 can be arranged diametrically opposite from one another about thecentral axis of the catheter 620 at a location near to the proximalconnector hub 615. In this embodiment, each of the recessed tabs 630includes a curved shape in which a concave major surface faces generallytoward the distal end of the catheter 620 while a convex minor surfacefaces generally toward the proximal connector hub 615. The pair ofrecessed tabs 630 can be directed to penetrate through the samepenetration point 32 as the catheter 620 for positioning in in thesubcutaneous layer 34 along the underside of the skin 30. As such, thepair of recessed tabs 630 can secure the catheter 620 in the operativeposition relative to the penetration point 32 without necessarilyrequiring adhesive tapes bonded to the skin.

In some embodiments, the pair of recessed tabs 630 can be integrallyformed with the flexible catheter 620 such that the pair of recessedtabs 630 and the catheter 420 share a common flexible polymer material.Accordingly, during insertion through the skin penetration point, eachof the recessed tabs 630 can flexibly adjust in a first direction(toward the proximal connector hub 615) so that each tab 630 nestswithin its corresponding cavity 632. After insertion of the recessedtabs 630 through the skin penetration point 32 and into the subcutaneouslayer 34, the recessed tabs 630 can be biased to extend outwardly fromthe circumferential wall of the catheter 620. In doing so, the pair ofrecessed tabs 630 can operate as subcutaneous anchors that engage theunderside of the skin 30, the fatty tissues in the subcutaneous layer34, or both so as to resist withdrawal of the intravenous cannula device605 from the skin penetration point 32. Thus, the intravenous cannuladevice 605 can be anchored in the operative position relative to thepenetration point 32 so that the distal tip of the flexible catheter 620resides in the targeted vessel 40 while the proximal connector hub 615resides external to the skin 30.

Referring to FIG. 6B, during removal of the intravenous cannula device605, each of the recessed tabs 630 can flexibly adjust in a seconddirection to bend or prolapse (in a distal direction away the proximalconnector hub 615). Thus, the recessed tabs 630 can be configured toprolapse in response to a removal force 640 applied to the intravenouscannula device 605 during withdrawal of the intravenous cannula device605 from the skin penetration point. Optionally, each of the recessedtabs 630 can include a second cavity (not shown) positioned distal ofthe respective tab 630 so as to receive at least a portion of the tab630 during removal through the skin penetration point 32.

Referring now to FIGS. 7A-7B, some alternative embodiments of a medicalsystem 700 may include an intravenous cannula device 705 that is similarto the device 605 illustrated in FIGS. 6A-6B, except that intravenouscannula device 705 is equipped with multiple pairs of recessed tabs 730that are operable to provide subcutaneous anchoring. Similar topreviously described embodiments herein, the medical system 700 includesthe intravenous cannula device 705 and an inserter tool 710 that isdetachably coupled to the intravenous cannula device 705. Theintravenous cannula device 705 can include a distal section having aflexible catheter 720 and a proximal connector hub 715 configured toreleasably connect with an external fluid line. In this embodiment, eachof the recessed tabs 730 is integrally formed as a unitary structurewith the side wall of the flexible catheter 720, and the pairs ofrecessed tabs 730 are positioned in series along a central region of theintravenous cannula device 705 (e.g., proximal to a distal tip of thecatheter 720 and distal to the proximal connector hub 715).

Similar to the embodiments previously described in connection with FIGS.6A-6B, one or more of the pairs of recessed tabs 730 can be directed topenetrate through the same penetration point 32 as the catheter 720 forpositioning in in the subcutaneous layer 34 along the underside of theskin 30. As such, one or more of the pairs of recessed tabs 730 cansecure the catheter 720 in the operative position relative to thepenetration point 32 without necessarily requiring adhesive tapes bondedto the skin. Each of the recessed tabs 730 inserted through the skinpenetration point 32 can flexibly adjust in a first direction (towardthe proximal connector hub 715) so that each tab 730 nests within itscorresponding cavity 732. After insertion of the respective pair ofrecessed tabs 730 through the skin penetration point 32 and into thesubcutaneous layer 34, the respective pair of recessed tabs 730 can bebiased to extend outwardly from the circumferential wall of the catheter720 (similar to the previous embodiments described in connection withFIGS. 6A-6B). In doing so, the respective pair of recessed tabs 730 canoperate as subcutaneous anchors that engage the underside of the skin30, the fatty tissues in the subcutaneous layer 34, or both so as toresist withdrawal of the intravenous cannula device 705 from the skinpenetration point 32. Thus, the intravenous cannula device 705 can beanchored in the operative position relative to the penetration point 32so that the distal tip of the flexible catheter 720 resides in thetargeted vessel 40 while the proximal connector hub 715 resides externalto the skin 30.

Referring to FIG. 7B, during removal of the intravenous cannula device705, each of the pairs of recessed tabs 730 passing through the skinpenetration point 32 can flexibly adjust in a second direction to bendor prolapse (in a distal direction away the proximal connector hub 715).Thus, the respective pair of recessed tabs 730 (when withdrawing throughthe skin penetration point 32) can be configured to prolapse in responseto a removal force 740 applied to the intravenous cannula device 705during withdrawal of the intravenous cannula device 705 from the skinpenetration point 32. Any of the recessed tabs 730 that are withdrawnthrough the skin penetration point 32 or are otherwise positionedexternal to the skin 30 can return to their non-prolapsed condition inwhich the recessed tabs 730 are biased to extend generally outward fromthe respective cavities 732. Optionally, each of the recessed tabs 730can include a second cavity (not shown) positioned distal of therespective tab 730 so as to receive at least a portion of the tab 730during removal through the skin penetration point 32.

Referring now to FIGS. 8A-8B, some alternative embodiments of a medicalsystem 800 may include a subcutaneous anchor 830 having a differentconfiguration, for example, in the shape of a slotted circumferentialring. In this embodiment, the medical system 800 can be similar to themedical system 100 of FIGS. 1-3. For example, the medical system 800includes an intravenous cannula device 805 and an inserter tool 810 thatis detachably coupled to the intravenous cannula device 805. Theintravenous cannula device 805 can include a distal section having aflexible catheter 820 and a proximal connector hub 815 configured toreleasably connect with an external fluid line. In this embodiment, theslotted circumferential ring 830 is integrally formed as a unitarystructure with the side wall of the flexible catheter 820, and theslotted circumferential ring 830 is positioned along a central region ofthe intravenous cannula device 805 (e.g., proximal to a distal tip ofthe catheter 820 and distal to the proximal connector hub 815).

The slotted circumferential ring 830 is formed radially about thecatheter 820 at a location near to the proximal connector hub 815. Theslotted circumferential ring 830 can be directed to penetrate throughthe same penetration point 32 as the catheter 820 for positioning in inthe subcutaneous layer 34 along the underside of the skin 30.Accordingly, the slotted circumferential ring 830 can secure thecatheter 820 in the operative position relative to the penetration point32 without necessarily requiring adhesive tapes bonded to the skin. Insome embodiments, the slotted circumferential ring 830 can be integrallyformed with the flexible catheter 820 such that the slottedcircumferential ring 830 and the catheter 820 share a common flexiblepolymer material. Accordingly, during insertion through the skinpenetration point, the slotted circumferential ring 830 can flexiblyadjust in a first direction so that the outer edge segments of theslotted circumferential ring 830 are shifted toward the circumferentialwall of the catheter 820 (in a proximal direction toward the proximalconnector hub 815). After insertion of the slotted circumferential ring830 through the skin penetration point 32 and into the subcutaneouslayer 34, the slotted circumferential ring 830 can be biased so that theouter edge segments extend generally radially outward from thecircumferential wall of the catheter 830. In doing so, the slottedcircumferential ring 830 can operate as a subcutaneous anchor thatengages the underside of the skin 30, the fatty tissues in thesubcutaneous layer 34, or both so as to resist withdrawal of theintravenous cannula device 805 from the skin penetration point 32. Theintravenous cannula device 805 can be anchored in the operative positionrelative to the penetration point 32 so that the distal tip of theflexible catheter 820 resides in the targeted vessel 40 while theproximal connector hub 815 resides external to the skin 30.

Referring to FIG. 8B, during removal of the intravenous cannula device805, the slotted circumferential ring 830 can flexibly adjust in asecond direction so that the outer edge segments of the slottedcircumferential ring 830 are shifted toward the circumferential wall ofthe catheter 820 (in a distal direction away the proximal connector hub815). As such, the flexible circumferential ring 830 can be configuredto prolapse in response to a removal force 840 applied to theintravenous cannula device 805 during withdrawal of the intravenouscannula device 805 from the skin penetration point 32.

Referring now to FIGS. 9A-9B, some alternative embodiments of a medicalsystem 900 may include an intravenous cannula device 905 that is similarto the device 805 illustrated in FIGS. 8A-8B, except that intravenouscannula device 905 is equipped with multiple subcutaneous anchors 930 inthe shape of slotted circumferential rings. Similar to previouslydescribed embodiments herein, the medical system 900 includes theintravenous cannula device 905 and an inserter tool 910 that isdetachably coupled to the intravenous cannula device 905. Theintravenous cannula device 905 can include a distal section having aflexible catheter 920 and a proximal connector hub 915 configured toreleasably connect with an external fluid line. In this embodiment, eachof the slotted circumferential rings 930 is integrally formed as aunitary structure with the side wall of the flexible catheter 920, andthe slotted circumferential rings 930 are positioned in series along acentral region of the intravenous cannula device 905 (e.g., proximal toa distal tip of the catheter 920 and distal to the proximal connectorhub 915).

Similar to the embodiments previously described in connection with FIGS.8A-8B, one or more of the slotted circumferential rings 930 can bedirected to penetrate through the same penetration point 32 as thecatheter 920 for positioning in in the subcutaneous layer 34 along theunderside of the skin 30. As such, one or more of the slottedcircumferential rings 930 can secure the catheter 920 in the operativeposition relative to the penetration point 32 without necessarilyrequiring adhesive tapes bonded to the skin. Each of the slottedcircumferential rings 930 inserted through the skin penetration point 32can flexibly adjust in a first direction so that the outer edge segmentsof the respective slotted ring 930 is shifted toward the circumferentialwall of the catheter 920 (in a proximal direction toward the proximalconnector hub 915). After insertion of the respective slotted ring 930through the skin penetration point 32 and into the subcutaneous layer34, the respective slotted ring 930 can be biased so that the outer edgesegments extend generally radially outward from the circumferential wallof the catheter 920. In doing so, the respective slotted ring 930 canoperate as a subcutaneous anchor that engages the underside of the skin30, the fatty tissues in the subcutaneous layer 34, or both so as toresist withdrawal of the intravenous cannula device 505 from the skinpenetration point 32. Thus, the intravenous cannula device 905 can beanchored in the operative position relative to the penetration point 32so that the distal tip of the flexible catheter 920 resides in thetargeted vessel 40 while the proximal connector hub 915 resides externalto the skin 30.

Referring to FIG. 9B, during removal of the intravenous cannula device905, each of the slotted circumferential rings 930 passing through theskin penetration point 32 can flexibly adjust in a second direction sothat the outer edge segments of the respective slotted ring 930 areshifted toward the circumferential wall of the catheter 920 (in a distaldirection away the proximal connector hub 915). Thus, the respectiveslotted ring 930 withdrawing through the skin penetration point 32 canbe configured to prolapse in response to a removal force 940 applied tothe intravenous cannula device 905 during withdrawal of the intravenouscannula device 905 from the skin penetration point 32. Any of theslotted circumferential rings 930 that are withdrawn through the skinpenetration point 32 or are otherwise positioned external to the skin 30can return to its non-prolapsed condition in which the slottedcircumferential ring 930 is biased to extend generally radially outwardfrom the circumferential wall of the catheter 920.

Referring now to FIGS. 10A-10B, some alternative embodiments of amedical system 1000 may include a subcutaneous anchor 1030 having adifferent configuration, for example, in the shape of an anchor flap. Inthis embodiment, the medical system 1000 can be similar to the medicalsystem 100 of FIGS. 1-3. For example, the medical system 1000 includesan intravenous cannula device 1005 and an inserter tool 1010 that isdetachably coupled to the intravenous cannula device 1005. Theintravenous cannula device 1005 can include a distal section having aflexible catheter 1020 and a proximal connector hub 1015 configured toreleasably connect with an external fluid line. In this embodiment, theanchor flap 1030 is integrally formed as a unitary structure with theside wall of the flexible catheter 1020, and the anchor flap 1030 ispositioned along a central region of the intravenous cannula device 1005(e.g., proximal to a distal tip of the catheter 1020 and distal to theproximal connector hub 1015).

Each recessed tab 1030 can include a corresponding cavity 1032 that isshaped to receive the anchor flap 1030 during insertion through the skinpenetration point 32. In this embodiment, the anchor flap 1030 includesa generally flat shape that extends transversely from the longitudinalaxis of the catheter 1020. The anchor flap 1030 can be directed topenetrate through the same penetration point 32 as the catheter 1020 forpositioning in in the subcutaneous layer 34 along the underside of theskin 30. As such, the anchor flap 1030 can secure the catheter 1020 inthe operative position relative to the penetration point 32 withoutnecessarily requiring adhesive tapes bonded to the skin.

In some embodiments, the anchor flap 1030 can be integrally formed withthe flexible catheter 1020 such that the anchor flap 1030 and thecatheter 1020 share a common flexible polymer material. Accordingly,during insertion through the skin penetration point, the anchor flap1030 can flexibly adjust in a first direction (toward the proximalconnector hub 1015) so that the anchor flap 1030 nests within itscorresponding cavity 1032. After insertion of the anchor flap 1030through the skin penetration point 32 and into the subcutaneous layer34, the anchor flap 1030 can be biased to extend outwardly from thecircumferential wall of the catheter 1020. In doing so, the anchor flap1030 can operate as subcutaneous anchors that engages the underside ofthe skin 30, the fatty tissues in the subcutaneous layer 34, or both soas to resist withdrawal of the intravenous cannula device 1005 from theskin penetration point 32.

Referring to FIG. 10B, during removal of the intravenous cannula device1005, the anchor flap 1030 can flexibly adjust in a second direction toprolapse (in a distal direction away the proximal connector hub 1015).Thus, the anchor flap 1030 can be configured to prolapse in response toa removal force 1040 applied to the intravenous cannula device 1005during withdrawal of the intravenous cannula device 1005 from the skinpenetration point 32. Optionally, the anchor flap 1030 can include asecond cavity (not shown) positioned distal of the anchor flap 1030 soas to receive at least a portion of the anchor flap 1030 during removalthrough the skin penetration point 32.

Referring now to FIGS. 11A-11B, some alternative embodiments of amedical system 1100 may include an intravenous cannula device 1105 thatis similar to the device 1005 illustrated in FIGS. 10A-10B, except thatintravenous cannula device 1105 is equipped with multiple anchor flaps1130 that are operable to provide subcutaneous anchoring. Similar topreviously described embodiments herein, the medical system 1100includes the intravenous cannula device 1105 and an inserter tool 1110that is detachably coupled to the intravenous cannula device 1105. Theintravenous cannula device 1105 can include a distal section having aflexible catheter 1120 and a proximal connector hub 1115 configured toreleasably connect with an external fluid line. In this embodiment, eachof the anchor flaps 1130 is integrally formed as a unitary structurewith the side wall of the flexible catheter 1120, and the anchor flaps1130 are positioned in series along a central region of the intravenouscannula device 1105 (e.g., proximal to a distal tip of the catheter 1120and distal to the proximal connector hub 1115).

Similar to the embodiments previously described in connection with FIGS.10A-10B, one or more of the anchor flaps 1130 can be directed topenetrate through the same penetration point 32 as the catheter 1120 forpositioning in in the subcutaneous layer 34 along the underside of theskin 30. In doing so, one or more of the anchor flaps 1130 can securethe catheter 1120 in the operative position relative to the penetrationpoint 32 without necessarily requiring adhesive tapes bonded to theskin. Each of the anchor flaps 1130 inserted through the skinpenetration point 32 can flexibly adjust in a first direction (towardthe proximal connector hub 1115) so that each of the respective flaps1130 nests within its corresponding cavity 1132. After insertion of therespective anchor flap 1130 through the skin penetration point 32 andinto the subcutaneous layer 34, the respective anchor flap 1130 can bebiased to extend outwardly from the circumferential wall of the catheter1120 (similar to the previous embodiments described in connection withFIGS. 6A-6B). In doing so, the respective anchor flap 1130 can operateas a subcutaneous anchor that engages the underside of the skin 30, thefatty tissues in the subcutaneous layer 34, or both so as to resistwithdrawal of the intravenous cannula device 1105 from the skinpenetration point 32.

Referring to FIG. 11B, during removal of the intravenous cannula device1105, each of the anchor flaps 1130 passing through the skin penetrationpoint 32 can flexibly adjust in a second direction to bend or prolapse(in a distal direction away the proximal connector hub 1115). Thus, therespective anchor flap 1130 withdrawing through the skin penetrationpoint 32 can be configured to prolapse in response to a removal force1140 applied to the intravenous cannula device 1105 during withdrawal ofthe intravenous cannula device 1105 from the skin penetration point 32.Any of the anchor flaps 1130 that are withdrawn through the skinpenetration point 32 or are otherwise positioned external to the skin 30can return to their non-prolapsed condition in which the anchor flaps1130 are biased to extend transversely to the longitudinal axis of thecatheter 1120. Optionally, each of the anchor flaps 1130 can include asecond cavity (not shown) positioned distal of the respective anchorflap 1130 so as to receive at least a portion of the respective anchorflap 1130 during removal through the skin penetration point 32.

Referring now to FIGS. 12A-12B, some alternative embodiments of amedical system 1200 may include a subcutaneous anchor 1230 having adifferent configuration, for example, in the shape of a taperedcircumferential ring. Similar to previously described embodiments, themedical system 1200 can include an intravenous cannula device 1205 andan inserter tool 1210 that is detachably coupled to the intravenouscannula device 1205. The intravenous cannula device 1205 can include adistal section having a flexible catheter 1220 and a proximal connectorhub 1215 configured to releasably connect with an external fluid line.In this embodiment, the tapered circumferential ring 1230 is integrallyformed as a unitary structure with the side wall of the flexiblecatheter 1220, and the tapered circumferential ring 1230 is positionedalong a central region of the intravenous cannula device 1205 (e.g.,proximal to a distal tip of the catheter 1220 and distal to the proximalconnector hub 1215).

The tapered circumferential ring 1230 can be directed to penetratethrough the same penetration point 32 as the catheter 1220 forpositioning in in the subcutaneous layer 34 along the underside of theskin 30. As such, the tapered circumferential ring 1230 can secure thecatheter 1220 in the operative position relative to the penetrationpoint 32 without necessarily requiring adhesive tapes bonded to theskin. In some embodiments, the tapered circumferential ring 1230 may beasymmetrical along its axis. For example, the tapered circumferentialring 1230 may include a proximal tapered face 1236 at a proximal endnearest to the proximal connector hub 1215. The proximal tapered face1236 may expand distally from an initial diameter (e.g., substantiallyequal to the diameter of the catheter 1220) at the proximal end of thetapered circumferential ring 1230 to a maximum diameter of the taperedcircumferential ring 1230 along the distal border of the proximaltapered face 1236. The diameter of the tapered circumferential ring 1230then reduces along one or more distal tapered sections 1237, 1238, and1239. In general, the slope of the proximal tapered face 1236 may besubstantially greater (e.g., steeper) than the aggregate slopes of thetapered sections 1237, 1238, and 1239. In some embodiments, suchlongitudinally asymmetrical configurations may reduce the relativeinsertion resistance while also increasing the relative withdrawalresistance of the tapered circumferential ring 1230 through thepenetration point 32.

After insertion of the tapered circumferential ring 1230 through theskin penetration point 32 and into the subcutaneous layer 34, thetapered circumferential ring 1230 can operate as a subcutaneous anchorthat engages the underside of the skin 30, the fatty tissues in thesubcutaneous layer 34, or both so as to resist withdrawal of theintravenous cannula device 1205 from the skin penetration point 32.During removal of the intravenous cannula device 1205 (FIG. 12B), thetapered circumferential rings 1230 withdrawing through the skinpenetration point 32 can be configured to pass through the skinpenetration point 32 in an atraumatic manner when a removal force 1240is applied to the intravenous cannula device 1205.

Referring now to FIGS. 13A-13B, some alternative embodiments of amedical system 1300 may include an intravenous cannula device 1305 thatis similar to the device 1205 illustrated in FIGS. 12A-12B, except thatintravenous cannula device 1305 is equipped with multiple taperedcircumferential rings 1330 positioned in a series. Similar to previouslydescribed embodiments herein, the medical system 1300 includes theintravenous cannula device 1305 and an inserter tool 1310 that isdetachably coupled to the intravenous cannula device 1305. Theintravenous cannula device 1305 can include a distal section having aflexible catheter 1320 and a proximal connector hub 1315 configured toreleasably connect with an external fluid line. In this embodiment, eachof the tapered circumferential rings 1330 is integrally formed as aunitary structure with the side wall of the flexible catheter 1320, andthe tapered circumferential rings 1330 are positioned in series along acentral region of the intravenous cannula device 1305 (e.g., proximal toa distal tip of the catheter 1320 and distal to the proximal connectorhub 1315).

Similar to the embodiments previously described in connection with FIGS.12A-12B, one or more of the tapered circumferential rings 1330 can bedirected to penetrate through the same penetration point 32 as thecatheter 1320 for positioning in in the subcutaneous layer 34 along theunderside of the skin 30. In doing so, one or more of the taperedcircumferential rings 1330 can secure the catheter 1320 in the operativeposition relative to the penetration point 32 without necessarilyrequiring adhesive tapes bonded to the skin. Each of the taperedcircumferential rings 1330 can include a proximal tapered face thatengages the underside of the skin 30, the fatty tissues in thesubcutaneous layer 34, or both so as to resist withdrawal of theintravenous cannula device 1305 from the skin penetration point 32.During removal of the intravenous cannula device 1305 (FIG. 13B), therespective tapered circumferential rings 1330 withdrawing through theskin penetration point 32 can be configured to pass through the skinpenetration point 32 in an atraumatic manner when a removal force 1340is applied to the intravenous cannula device 1305.

Referring now to FIGS. 14A-14B, some alternative embodiments of amedical system 1400 may include an intravenous cannula device 1405 thatis similar to the device 105 illustrated in FIGS. 1-3, except thatintravenous cannula device 1405 is equipped with multiple texturedcutouts 1430. Similar to previously described embodiments herein, themedical system 1400 includes the intravenous cannula device 1405 and aninserter tool 1410 that is detachably coupled to the intravenous cannuladevice 1405. The intravenous cannula device 1405 can include a distalsection having a flexible catheter 1420 and a proximal connector hub1415 configured to releasably connect with an external fluid line. Inthis embodiment, the textured cutouts 1430 include sidewalls integrallyformed as a unitary structure with the side wall of the flexiblecatheter 1320, and the textured cutouts 1430 are positioned in seriesalong a central region of the intravenous cannula device 1405 (e.g.,proximal to a distal tip of the catheter 1420 and distal to the proximalconnector hub 1415). In the depicted embodiment, the textured cutouts1430 may be formed in the sidewall of the flexible catheter 1420 as aset of scalloped cavities configured to anchor within the subcutaneouslayer. Some or all of the textured cutouts 1430 can be directed topenetrate through the same penetration point 32 as the catheter 1420 forpositioning in in the subcutaneous layer 34 along the underside of theskin 30. In doing so, one or more of the textured cutouts 1430 cansecure the catheter 1420 in the operative position relative to thepenetration point 32 without necessarily requiring adhesive tapes bondedto the skin. Each of the textured cutouts 1430 can include a least onecavity sidewall that engages the underside of the skin 30, the fattytissues in the subcutaneous layer 34, or both so as to resist withdrawalof the intravenous cannula device 1405 from the skin penetration point32. During removal of the intravenous cannula device 1405 (FIG. 14B),the respective textured cutouts 1430 withdrawing through the skinpenetration point 32 can be configured to pass through the skinpenetration point 32 in an atraumatic manner when a removal force 1440is applied to the intravenous cannula device 1405.

Referring now to FIGS. 15A-15B, some alternative embodiments of amedical system 1500 may include an intravenous cannula device 1505 thatis similar to the device 105 illustrated in FIGS. 1-3, except thatintravenous cannula device 1505 is equipped with a threaded anchor 1530.Similar to previously described embodiments herein, the medical system1500 includes the intravenous cannula device 1505 and an inserter tool1510 that is detachably coupled to the intravenous cannula device 1505.The intravenous cannula device 1505 can include a distal section havinga flexible catheter 1520 and a proximal connector hub 1515 configured toreleasably connect with an external fluid line. In this embodiment, thethreaded anchor 1530 include at least one thread pattern formed as aunitary structure with the side wall of the flexible catheter 1520, andthe threaded anchor 1530 is positioned along a central region of theintravenous cannula device 1505 (e.g., proximal to a distal tip of thecatheter 1520 and distal to the proximal connector hub 1515). In thedepicted embodiment, the threaded anchor 1530 may be spiral around theside wall of the flexible catheter 1520 so that the thread is configuredto anchor within the subcutaneous layer. The threaded anchor 1530 can bedirected to penetrate through the same penetration point 32 as thecatheter 1520 for positioning in in the subcutaneous layer 34 along theunderside of the skin 30. For example, during insertion of theintravenous cannula device 1505, the user can twist the inserter tool1510 to “screw” the anchor thread through the skin penetration point 32.In doing so, the threaded anchor 1530 can secure the catheter 1520 inthe operative position relative to the penetration point 32 withoutnecessarily requiring adhesive tapes bonded to the skin. The threadedanchor 1530 can include a least one thread wall surface that engages theunderside of the skin 30, the fatty tissues in the subcutaneous layer34, or both so as to resist withdrawal of the intravenous cannula device1505 from the skin penetration point 32. During removal of theintravenous cannula device 1505 (FIG. 15B), the threaded anchor can beremoved through the skin penetration point 32 by twisting the proximalconnector hub 1515 with a removing force 1540 so as to “unscrew” thethreaded anchor 1530 out of the skin penetration point 32 in anatraumatic manner.

Referring now to FIGS. 16A-16B, some alternative embodiments of amedical system 1600 may include an intravenous cannula device 1605 thatis similar to the device 105 illustrated in FIGS. 1-3, except thatintravenous cannula device 1605 is equipped with a wedge anchor 1630.Similar to previously described embodiments herein, the medical system1600 includes the intravenous cannula device 1605 and an inserter tool1610 that is detachably coupled to the intravenous cannula device 1605.The intravenous cannula device 1605 can include a distal section havinga flexible catheter 1620 and a proximal connector hub 1615 configured toreleasably connect with an external fluid line. The wedge anchor 1630can be positioned along a central region of the intravenous cannuladevice 1605 (e.g., proximal to a distal tip of the catheter 1620 anddistal to the proximal connector hub 1615). In the depicted embodiment,the wedge anchor 1630 is asymmetrical in shape. For example, in a crosssectional view taken parallel to the longitudinal axis of the catheter1620, the wedge anchor 1630 may appear generally trapezoidal in shape,in which the upper and lower sides of the trapezoid are substantiallyparallel to the axis of the catheter 1620, and a proximal side has asteeper angle than a distal side. In some embodiments, thislongitudinally asymmetrical configuration can reduce the relativeinsertion resistance while also increasing the relative extractionresistance of the wedge anchor 1630 through the penetration point 32.

The wedge anchor 1630 can be directed to penetrate through the samepenetration point 32 as the catheter 1620 for positioning in in thesubcutaneous layer 34 along the underside of the skin 30. In doing so,the wedge anchor 1630 can secure the catheter 1620 in the operativeposition relative to the penetration point 32 without necessarilyrequiring adhesive tapes bonded to the skin. The wedge anchor 1630 caninclude a least one sidewall (e.g., the aforementioned steep proximalside wall) that engages the underside of the skin 30, the fatty tissuesin the subcutaneous layer 34, or both so as to resist withdrawal of theintravenous cannula device 1605 from the skin penetration point 32.During removal of the intravenous cannula device 1605 (FIG. 16B), theuser can lightly move the intravenous cannula device 1605 in aback-and-forth lateral movement while applying a longitudinal withdrawalforce 1640 so that the wedge anchor 1630 passes through the skinpenetration point 32 in an atraumatic manner.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the scope of the invention. Accordingly,other embodiments are within the scope of the following claims.

What is claimed is:
 1. A medical system for anchoring an intravenouscannula device in a subcutaneous region along an underside of a skinlayer, comprising: an intravenous cannula device including a flexiblecatheter, a proximal connector hub, and a subcutaneous anchor integrallyformed as a unitary structure with an outer wall of the flexiblecatheter, the flexible catheter including a lumen and extending distallyof the proximal connector hub, and the proximal connector hub includinga thread pattern configured to releasably connect with an external fluidline; and an inserter tool removably coupled to the intravenous cannuladevice so as to insert the flexible catheter of the intravenous cannuladevice through a skin penetration point and into a targeted vessel, theinserter tool including a handle and an insertion needle extendingdistally from the handle, the insertion needle being slidably engagedwith the lumen of the flexible catheter of the intravenous cannuladevice, wherein the inserter tool is removable from the intravenouscannula device when the insertion needle is proximally withdrawn fromthe lumen of the flexible catheter, wherein the subcutaneous anchor ispositioned between a distal tip of the flexible catheter and theproximal connector hub, and wherein the subcutaneous anchor includes atleast one surface to engage tissue in a subcutaneous region along anunderside of a skin layer when the flexible catheter of the intravenouscannula device is inserted through a skin penetration point and into atargeted vessel.
 2. The system of claim 1, wherein the subcutaneousanchor comprises one or more flexible circumferential rings integrallyformed as a unitary structure with the outer wall of the flexiblecatheter.
 3. The system of claim 1, wherein each of the one or moreflexible circumferential rings are configured to prolapse and extendtoward a distal end of the flexible catheter during removal through theskin penetration point.
 4. The system of claim 1, wherein thesubcutaneous anchor comprises one or more pairs of recessed tabsintegrally formed as a unitary structure with the outer wall of theflexible catheter, wherein each respective recessed tab includes acorresponding cavity to receive the recessed tab during insertionthrough the skin penetration point.
 5. The system of claim 1, whereineach of the one or more pairs of recessed tabs are configured toprolapse such that free ends of the recessed tabs extend toward a distalend of the flexible catheter during removal through the skin penetrationpoint.
 6. The system of claim 1, wherein each of the one or more pairsof recessed tabs are configured to provide a generally curved shape inwhich a convex surface faces generally toward the proximal connectorhub.
 7. The system of claim 1, wherein the subcutaneous anchor comprisesone or more slotted circumferential rings integrally formed as a unitarystructure with the outer wall of the flexible catheter.
 8. The system ofclaim 1, wherein each of the one or more slotted circumferential ringsare configured to prolapse and extend toward a distal end of theflexible catheter during removal through the skin penetration point. 9.The system of claim 1, wherein the subcutaneous anchor comprises one ormore anchor flaps integrally formed as a unitary structure with theouter wall of the flexible catheter, wherein each of the one or moreanchor flaps comprises a generally straight body that extendstransversely to a longitudinal axis of the flexible catheter.
 10. Thesystem of claim 1, wherein each of the one or more anchor flaps areflexible and configured to prolapse such that free ends of the one ormore anchor flaps extend toward a distal end of the flexible catheterduring removal through the skin penetration point.
 11. The system ofclaim 1, wherein the subcutaneous anchor comprises one or more taperedcircumferential rings integrally formed as a unitary structure with theouter wall of the flexible catheter, wherein each of the taperedcircumferential rings have an asymmetric shape in which a proximal faceis steeper than a distal tapered face.
 12. The system of claim 1,wherein the subcutaneous anchor comprises a set of textured cutoutsintegrally formed as a unitary structure with the outer wall of theflexible catheter, wherein each of the textured cutouts are defined bycavity walls formed in the outer wall of the flexible catheter.
 13. Thesystem of claim 1, wherein the subcutaneous anchor comprises a threadedanchor integrally formed as a unitary structure with the outer wall ofthe flexible catheter, wherein the threaded anchor comprises a raisedthread pattern helically extending around the outer wall of the flexiblecatheter.
 14. The system of claim 1, wherein the subcutaneous anchorcomprises a wedge anchor integrally formed as a unitary structure withthe outer wall of the flexible catheter, wherein the wedge anchorcomprises an asymmetric shape having a proximal face and a distal face,the proximal face defines an incline relative to the outer wall of theflexible catheter that is greater than an incline defined by the distalface.
 15. A method of using an intravenous cannula device, comprising:inserting a needle portion of an inserter tool through a skinpenetration point and into a targeted vessel, wherein an intravenouscannula device is removably coupled to the inserter tool such that aflexible catheter of the intravenous cannula device is advanced throughthe skin penetration point and into the targeted vessel while asubcutaneous anchor integrally formed as a unitary structure with anouter wall of the flexible catheter is positioned in a subcutaneousregion along an underside of a skin layer; removing the inserter toolfrom the intravenous cannula device such that the needle portion of theinserter tool is slidably withdrawn from a lumen of the flexiblecatheter while the flexible catheter remains in the targeted vessel andthe subcutaneous anchor remains in the subcutaneous region along theunderside of the skin layer; and threadably engaging an external fluidline to a proximal connector hub of the intravenous cannula device whilethe flexible catheter remains in the targeted vessel and thesubcutaneous anchor remains in the subcutaneous region along theunderside of the skin layer, wherein the subcutaneous anchor ispositioned between a distal tip of the flexible catheter and theproximal connector hub, and wherein the subcutaneous anchor includes atleast one surface to engage tissue in the subcutaneous region proximateto the skin penetration point.
 16. The method of claim 15, furthercomprising infusing a fluid from the proximal connector hub through thelumen of the flexible catheter and into the targeted vessel.
 17. Themethod claim 15, further comprising applying a withdrawal force to theproximal connector hub of the intravenous cannula device so as towithdrawal the subcutaneous anchor through the skin penetration point.18. A medical system for anchoring an intravenous cannula device in asubcutaneous region along an underside of a skin layer, comprising: anintravenous cannula device including a flexible catheter, a proximalconnector hub, and a subcutaneous anchor positioned between a distal tipof the flexible catheter and the proximal connector hub; and an insertertool removably coupled to the intravenous cannula device, the insertertool including a handle and an insertion needle extending distally fromthe handle, the insertion needle being slidably engaged with a lumen ofthe flexible catheter, wherein the subcutaneous anchor includes at leastone surface to engage tissue in a subcutaneous region along an undersideof a skin layer when the flexible catheter of the intravenous cannuladevice is into a targeted vessel.
 19. The system of claim 18, whereinthe subcutaneous anchor comprises at least one of: one or more flexiblecircumferential rings, one or more pairs of recessed tabs, one or moreslotted circumferential rings, one or more anchor flaps, one or moretapered circumferential rings, a set of textured cutouts, a threadedanchor, and a wedge anchor.
 20. The system of claim 18, wherein theinsertion needle is fixedly positioned relative to the handle of theinserter tool.